Active-matrix organic light emitting diodes (AMOLEDs) have been recognized as promising next-generation displays for replacing liquid crystal displays (LCDs). However, as consumers' consumption levels increase, high-resolution products become a key development direction of display products. Unfortunately, high-resolution AMOLED products can hardly compete with LCDs, because the organic layer structures of organic light emitting displays are usually prepared by mask evaporation method, and the mask evaporation method has several drawbacks, such as difficulty in alignment, low yield, inability to realize light emitting in smaller pixel areas, inability to accurately control evaporation areas, and thus such AMOLED products cannot meet the rapidly growing need for high-resolution displays. On the other hand, an organic light emitting layer prepared by printing method instead of mask evaporation method has extremely limited resolution. Therefore, high-resolution AMOLED products encounter several problems, like high technical difficulty, low product yield, and high commodity price.
Quantum dots (QDs), also known as nanocrystals, are nanoparticles composed of Groups II-VI or III-V elements. Since electrons and holes are confined by quantum, a continuous band structure will become a discrete energy level structure with molecular properties. After being excited, QDs may emit fluorescence. The luminescence spectrum thereof may be controlled by changing the size of QDs, and the fluorescence intensity and stability are both good. Thus, QDs is a very good electroluminescent material.
With the further development of quantum-dot technology, the researches on electroluminescent quantum-dot light emitting diodes have been becoming further, and quantum efficiency has been continuously improved and basically reached the industrialization level. It has become trends and the future to employ new processes and technologies so as to achieve industrialization of the electroluminescent quantum-dot light emitting diodes. In order to improve the resolution of organic light emitting diodes (OLEDs), there are needs to modify the OLED evaporation mask plate to further reduce the line width in the mask process, to use a higher-precision print head, etc. These needs are often difficult to be satisfied in large-scale production process.